In December, British Airways will add an unlikely route to its daily schedule: a 54-mile short flight between the island nation of Bahrain and Dammam, in Saudi Arabia. To put that stretch into context, it's about half the distance between New York and Philadelphia. Currently, the airline connects those cities via the 90-minute BA 8499, a limo service that’s assigned its own flight number; the airborne alternative should cut that time by two-thirds.

This is far from the only ultra-short-haul journey in the world, though. The record holder for the world's shortest commercial flight is scheduled for just 90 seconds. In good conditions, Loganair’s 1.7-mile jaunt between the Scottish islands of Westray (population: 640) and Papa Westray (population: 72) in the Orkneys, off the north coast of the mainland, can take under a minute. Headwinds can make the flight a whopping two-and-a-half minutes. Retired police officer Graham Maben is one of the route’s regulars; the 70-year-old Orkney native now runs a tour business on the islands, and estimates he has taken the flight around 40 times over the past 15 years. “There are three regular pilots who work to a rota to provide the service, and yes, we know them all. We always have a quick catch-up while the plane is on the ground,” he says.

In an era when airlines are increasingly emphasizing ultra-long-haul routes—see the current record holder, the nearly 19-hour, 9,500-mile flight from Newark to Singapore—all these short journeys seem outliers. At best, whether in Orkney or Bahrain, they seem quirky and counter-intuitive; at worst, these taxi-like trips are environmentally irresponsible. So why is there such a vibrant market for these taxi-like flights? It’s a combination of the low cost of fuel and, frankly, the lack of other options to get from A to B.

Alaska’s so-called milk runs, which travel between isolated communities like Ketchikan and Sitka, are often holdovers from aviation’s Golden Era, when plane ranges were more limited and refueling required them to shuttle, almost skittishly, between nearby airports. Another mid-century convention, the Chicago Convention of 1944, underwrites the system, too, according to environmental sociologist Roger Tyers. A global roster of governments gathered in the Midwest to establish the rules for a nascent, international aviation industry. To avoid petty squabbles over taxation, this pow-wow agreed that airplane fuel would be exempt from most duties. “The goal was to kickstart a fledgling industry,” Tyers says, “But it was that tax regime which helped aviation become what it is today.” In other words, the relative cheapness of aviation fuel encourages airlines to operate routes where a car journey might be an easy alternative. It also allows airlines to schedule 40-minute flights like those between San Diego and Los Angeles, which might not be profitable on their own but help feed passengers into an airline’s network and book long-haul tickets from a hub like LAX.

Of course, many of these ultra-short-haul legs operate precisely because other options are difficult or impossible. Roiling seas around the Orkneys make boat journeys stomach-churning and more vulnerable to cancelation; Alaska’s milk runs operate between settlements that are unconnected by passable roads. The new Bahrain route has likely been put in place for efficiency, per retired pilot John Cox, who writes USA Today’s Ask The Captain. Cox used to fly in and out of Bahrain frequently; the western-friendly nation was a popular destination for expats living in the Gulf, who would spend the weekend on its beaches. “There’s just one causeway between Bahrain and Dammam,” he says, “I’ve seen it take 40 minutes, and I’ve seen the journey take four hours, particularly on Fridays and Sundays. The customs officials on both sides are very thorough.” No wonder business travelers would prefer the reliability of a scheduled short-haul flight.

And although aviation is a high-profile source of carbon dioxide pollution, it only contributes 3.5 percent of global emissions currently, far lower than industries like farming. The environmental impact of these ultra-short-haul routes won’t be high priority for a few decades, according to Greenpeace’s John Sauven. But as other industries innovate, the aviation business will need to catch up. “As every other sector de-carbonizes, what you’re left with is more aviation,” he explains, citing estimates that suggest aviation’s unwillingness to adopt alternative fuel sources will push its share of emissions to more than 21 percent by 2050.

The good news is that newer planes will certainly offset some of these challenges—like Virgin’s Airbus A350, whose engines will generate 30 percent less carbon dioxide than its current Boeing 747-400. But you don't have to wait for the airlines or aircraft tech to catch up to reduce your environmental footprint. Those concerned with their carbon footprint can proactively invest in carbon offsets. Look for two key phrases to verify that your investment will truly counterbalance each mile flown: VCS, or verified carbon standard, and Gold Standard VER. Both guarantee that any offset scheme is inspected and certified.

Most short-haul critics don’t focus their ire on services that offer a lifeline to local communities with little alternative, like the Orkneys, nor on long-haul journeys over water. (In fact, some data suggests that long-haul flights are less polluting as cruising burns through less fuel than take-off or landing, lowering emissions per mile). The major target, instead, is short-haul, landlocked trips, which could easily be swapped-out for an alternative method. Roger Tyers says that research shows most travelers are willing to take other options, like a train, for any journey four hours and under—London to Paris by Eurostar, for example. Here in America, where the train network is less extensive than in Europe, he suggests adjusting our approach to short-haul trips. Quality, not quantity, says Tyers: if you’re living out of state, visit your mom for two week-long stints per year instead of six weekends. Mom won’t love you any less.